Does anyone have experience with changing from a three vane water pump to a five vane water pump and seeing a difference? This question pertains to a 425.
Don't forget the pulleys were smaller also to spin the pump faster. IF I remember correctly the A/C cars spun at 1.1 times engine speed. Non A/C spun at something like .9 Tom T.
A three vane pump would move the water slower so the water would be in the radiator longer and give up more heat. But it would be in the engine longer and collect more heat so maybe it works out the same.
Higher flow rate is always better until you get so high that cavitation and other stuff becomes a detriment. Good reading here, see pages 2/7 and 3/7: https://www.enginebasics.com/Engine Basics Root Folder/Engine Cooling Pg2.html Devon
I agree. back in the days when we raced a 255-inch Mercury flathead, we had to grind off every other water pump vane (two water pumps) because the water moved so fast that it would neither pick up enough heat from the engine, nor get rid of enough of it in the radiator . We didn't run thermostats (there were two of them also), but instead had restrictors in their place. Removing the vanes solved the overheating issue.
I don't doubt that removing vanes fixed an overheating issue, but it's not because the coolant was "moving too fast" to pick-up or release heat. The pump was cavitating, so the coolant wasn't moving fast enough due to pumping inefficiency.
